Submarine Power Cable Having Sections With Different Water Permeability

Abstract

A submarine power cable including a conductor, an insulation system arranged around the conductor, the insulation system including an inner semiconducting layer, an insulation layer arranged around the inner semiconducting layer, and an outer semiconducting layer arranged around the insulation layer, and a polymeric sheath arranged around the insulation system, wherein the first section has a mechanically flexible sheath arranged around the insulation system, wherein the mechanically flexible sheath has a lower radial water permeability than a radial water permeability of any layer arranged outside the insulation system in the second sections.

1 . A submarine power cable comprising a conductor, an insulation system arranged around the conductor, the insulation system having an inner semiconducting layer, an insulation layer arranged around the inner semiconducting layer, and an outer semiconducting layer arranged around the insulation layer, and a polymeric sheath arranged around the insulation system, wherein the submarine power cable has a first section arranged axially between two second sections, wherein the first section has a mechanically flexible sheath arranged around the insulation system, wherein the mechanically flexible sheath has a lower radial water permeability than a radial water permeability of any layer arranged outside the insulation system in the second sections. 
     
     
         2 . The submarine power cable as claimed in  claim 1 , wherein the mechanically flexible sheath is a water blocking layer arranged around the insulation system along at least 20% of the length of the first section, such as along the entire first section. 
     
     
         3 . The submarine power cable as claimed in  claim 2 , wherein the water blocking layer is a metallic water blocking layer. 
     
     
         4 . The submarine power cable as claimed in  claim 3 , wherein the metallic water blocking layer is a longitudinally welded metal sheath, an extruded metal sheath, or a longitudinally bonded laminated sheath. 
     
     
         5 . The submarine power cable as claimed in  claim 1 , wherein each of the two second sections are longer than the first section. 
     
     
         6 . The submarine power cable as claimed in  claim 1 , wherein the first section is at least 1 m, such as at least 2 m, such as at least 3 m. 
     
     
         7 . The submarine power cable as claimed in  claim 1 , wherein the first section is at most 200 m, such as at most 150 m, such as at most 100 m, such as at most 50 m. 
     
     
         8 . The submarine power cable as claimed in  claim 1 , wherein each second section is at least 500 m long, such as at least 1000 m long, such as at least 5000 m long. 
     
     
         9 . The submarine power cable as claimed in  claim 1 , comprising a joint arranged in the first section. 
     
     
         10 . The submarine power cable as claimed in  claim 9 , wherein the joint comprises a conductor joint and a joint insulation system arranged around the conductor joint. 
     
     
         11 . The submarine power cable as claimed in  claim 10 , wherein the joint insulation system is a vulcanized joint insulation system or comprises a prefabricated elastomeric sleeve. 
     
     
         12 . The submarine power cable as claimed in  claim 1 , comprising a water swellable tape arranged between the insulation system and the polymeric sheath along the entire second sections. 
     
     
         13 . The submarine power cable as claimed in  claim 1 , comprising a water swellable tape arranged between the insulation system and the polymeric sheath along the entire first section. 
     
     
         14 . The submarine power cable as claimed in  claim 1 , wherein the submarine power cable is an AC power cable or a DC power cable. 
     
     
         15 . The submarine power cable as claimed in  claim 1 , comprising an outer sheath or outer serving, which is the outermost layer of the submarine power cable, wherein the outer sheath or outer serving extends along a majority of or the entire length of the first section. 
     
     
         16 . The submarine power cable as claimed in  claim 2 , wherein each of the two second sections are longer than the first section. 
     
     
         17 . The submarine power cable as claimed in  claim 2 , wherein the first section is at least 1 m, such as at least 2 m, such as at least 3 m. 
     
     
         18 . The submarine power cable as claimed in  claim 2 , wherein the first section is at most 200 m, such as at most 150 m, such as at most 100 m, such as at most 50 m. 
     
     
         19 . The submarine power cable as claimed in  claim 2 , wherein each second section is at least 500 m long, such as at least 1000 m long, such as at least 5000 m long. 
     
     
         20 . The submarine power cable as claimed in  claim 2 , comprising a joint arranged in the first section.